[Predictive value of leukocyte derived markers for postoperative delirium after cardiac valve surgery]

To explore the predictive value of leukocyte derived markers for postoperative delirium (POD) in patients undergoing cardiac valve surgery.

A prospective cohort study was conducted. The patients who underwent cardiac valve surgery admitted to Beijing Anzhen Hospital of Capital Medical University from October 2021 to March 2023 were enrolled. The demographic, baseline and perioperative data were collected, and the neutrophil to lymphocyte ratio (NLR) and platelet to white blood cell ratio (PWR) were calculated before operation and within 24 hours after operation. Delirium assessment was conducted twice a day for patients within 1-5 days after surgery or discharged within 5 days. According to the evaluation results, the patients were divided into delirium group and non-delirium group. The clinical indexes between the two groups were compared. Multivariate Logistic regression analysis was used to screen the independent risk factors of POD, and the POD predictive model was constructed. The predictive value of POD predictive model was evaluated by receiver operator characteristic curve (ROC curve).

A total of 235 patients were enrolled in the analysis, of which 83 patients had POD (35.32%) and 152 patients did not have POD (64.68%). Compared with the non-delirious group, the patients in the delirious group had higher Charlson comorbidity index (CCI) score and lower mini-mental state examination (MMSE) score. In terms of perioperative data, compared with the non-delirium group, the patients in the delirium group had longer operative time, duration of cardiopulmonary bypass, length of intensive care unit (ICU) stay, duration of mechanical ventilation, and postoperative hospital stay, higher incidence of perioperative atrial fibrillation, and lower discharge life score. In terms of leukocyte derived markers, NLR within 24 hours after surgery in both groups were significantly higher than those before surgery, and PWR were significantly lower than those before surgery. The NLR within 24 hours after surgery, PWR difference and NLR difference in the delirium group were significantly higher than those in the non-delirium group. Multivariate Logistic regression analysis showed that CCI score [odds ratio (OR) = 1.394, 95% confidence interval (95%CI) was 1.038-1.872, P = 0.027], perioperative atrial fibrillation (OR = 3.697, 95%CI was 1.711-7.990, P < 0.001), duration of cardiopulmonary bypass (OR = 1.008, 95%CI was 1.002-1.015, P = 0.016), length of ICU stay (OR = 1.006, 95%CI was 1.002-1.010, P = 0.002), NLR difference (OR = 1.029, 95%CI was 1.009-1.050, P = 0.005) and PWR difference (OR = 1.044, 95%CI was 1.009-1.080, P = 0.013) were independently correlated with POD. POD predictive model was constructed by multivariate Logistic regression analysis result: POD predictive model index = -4.970+0.336×CCI score+1.317×perioperative atrial fibrillation+0.009×duration of cardiopulmonary bypass+0.006×length of ICU stay+0.030×NLR difference+0.044×PWR difference. ROC curve analysis showed that the area under the ROC curve (AUC) of NLR difference for predicting POD was 0.659 (95%CI was 0.583-0.735), the optimal critical value was 16.62, the sensitivity was 60.2%, and the specificity was 70.4% (P < 0.05). The AUC of PWR difference for predicting POD was 0.608 (95%CI was 0.528-0.688), the optimal critical value was 25.68, the sensitivity was 51.8%, and the specificity was 75.7% (P < 0.05). The AUC of POD predictive model for predicting POD was 0.805 (95%CI was 0.745-0.865), the optimal critical value was 0.39, the sensitivity was 74.7%, and the specificity was 79.6% (P < 0.05).

The differences of NLR and PWR are independently related to POD, which has potential value in predicting POD after cardiac valve surgery.